System And Method Of Assembly Of CPVC Fire Sprinkler System Employing Mechanical Couplings And Supports

ABSTRACT

Fire sprinkler system comprising a network of CPVC pipe lengths in which at least some of the pipe lengths are interconnected with mechanical devices having resilient sealing members that are chemically compatible with the CPVC composition. Repairs and system modifications can be made without the use of solvent cement. In-line joints are formed with a coupling device including a pair of arcuate coupling segments having a first end, a second end, and an interior concave surface extending between the first end and the second end. A longitudinal channel extends along the concave surface. At least one mechanical fastener is operative to detachably connect the pair of coupling segments. A resilient annular seal is located within the longitudinal channel of each segment. A branching device connects a branch pipe to a main pipe through an orifice in the main pipe utilizing a saddle-like sealing member. The pipe assemblies are able to pass UL testing protocols for wet fire sprinkler systems.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims benefit pursuant to 35 U.S.C. §119(e) ofProvisional Application No. 60/714,563 filed on Sep. 7, 2005.

FIELD OF THE INVENTION

The invention relates generally to fire sprinkler systems comprisingCPVC pipes. An exemplary embodiment provides for mechanicalinterconnection of pipe lengths without the use of solvent cement andthe utilization of resilient sealing members chemically compatible withthe CPVC composition.

BACKGROUND OF THE INVENTION

Many buildings are required by code to have fire suppression sprinklersystems. Further, residential structures are increasingly being providedwith fire suppression systems. CPVC piping systems are ideally suitedfor fire sprinkler system applications because of their resistance tocorrosion, the lightness of material, ease of installation, and otherdesirable properties.

Under current standards, in-line coupling of abutting CPVC pipe sectionsis accomplished by use of solvent cement techniques to form a permanentbond therebetween. Such techniques require sufficient time for thesolvent cement to cure. Furthermore, at times it may become necessary tomake modifications or repairs to existing CPVC fire sprinkler systems.The use of solvent cement demands that the modification to the pipenetwork be accomplished in a generally dry environment.

In use, fire sprinkler systems are often under continuous waterpressure. In prior systems, for a system modification or repair, thetargeted sprinkler section must be removed from service and drained. Thenew CPVC pipe sections must be connected into the system adhered bysolvent cement which requires an applicable cure time. Thereafter, thesystem is brought back online and tested. During this process, which mayextend over 24 hours or longer, at least a portion of the fire sprinklersystem is out of service, requiring an alternate fire watch. Thus, thereexists a need to provide a method to join CPVC piping which eliminatesthe down time associated with prior joining processes.

Use of the solvent cement creates an irreversible pipe connection. Thus,misalignment or other adverse conditions cannot be readily corrected.Further, some piping systems, such as piping used in some foodpreparation systems, require frequent disassembly for cleaning. Thus,there exists a need in the art for a CPVC piping system that joins pipesegments in a releasable manner.

Other piping systems such as those using metal pipes or plastic materialsuch as PVC, may utilize mechanical couplings with grooved or rolledpipes. Some mechanical couplings employ an annular resilient sealingmember to engage the closely abutting pipe ends. Commonly, the sealingmembers are formed of elastomeric compositions employing plasticizers orother agents. Lubricants are also commonly applied for ease ofinstallation. However, such prior techniques cannot readily betransferred for use with CPVC piping. The CPVC piping may havecompatibility issues with the plasticizers or lubricants which couldcause stress cracks in the pipe material.

In PVC piping, a method of grooving the pipe near the cut end is called“rolled grooving”. In rolled grooving, material is pressed inwardly toform a circumferential depression on the outer surface. The displacedmaterial in this process effectively reduces the inner diameter of thepipe. The reduced inner diameter affects fluid flow. Also, the characterand properties of CPVC does not readily lend itself to a rolled groovingprocess.

In some other grooving processes, pipe wall material is removed by ablade or other cutting implement. For example, grooving metal conduitsmay be accomplished with a cutting tool. However, the prevalent teachingwith respect to CPVC piping is that CPVC should not be grooved. CPVCfire sprinkler systems have to meet stringent UL and other standards.Because wall thickness is decreased during a cutting or groovingprocess, grooving CPVC pipe has been discouraged to prevent weakening ofthe pipe wall. Thus, prior pipe system processing and sealing methodsare not readily adapted to CPVC piping systems. There exists a need formethods and testing procedures for a system employing grooved CPVCpiping including a seal compatibility protocol.

Further, mechanical couplings often rely on compression forces toprovide a sealing engagement between the pipes and the sealing member.The compression force applied to CPVC pipe must not exceed predeterminedlimits. Thus, to employ mechanical compression-type fittings with CPVCsystems, there exists a need for a compression limiting mechanism.

Other desired configurations or modifications of a CPVC pipe network mayinclude branched connections from a first pipe line to a perpendicularpipe line. In the art, a cut-in to an existing CPVC fire sprinklersystem is made by shutting down the system and draining. An appropriatesocket style tee fitting is used in combination with socket unions,grooved coupling adapters, and flanges. The fitting is adhered to thecut pipe ends using solvent cement. Care must be taken to follow cut-incure schedules for the solvent cement. Similar to in-line coupling, theprocess requires considerable down time of the sprinkler system as wellas an alternate fire watch method. Thus, there exists a need in the artfor cut-in fittings and procedures that significantly reduce downtime ofthe sprinkler system, while still providing a system that meetsstringent fire protection standards.

If mechanical couplings and fittings are to be used with CPVC pipesystems, such items must be utilized in ways that accommodate theproperties of the CPVC piping. Compression and support requirements ofthe CPVC material must be met. Thus, there exists a need for mechanicalfixtures that are compatible with the properties of CPVC piping.

Also, as discussed above, mechanical fittings have a major drawback inthat elastomeric sealing members are often made of compositionscomprising plasticizers and other agents that can degrade or impairperformance of CPVC piping. Thus, there exists a need to provide acompatibility protocol with the use of mechanical fittings with CPVCpiping.

Further, certain fire testing standards have been developed that arespecific to plastic piping systems. Incorporation of mechanical fittingsand adapters into such systems requires that the hybrid system meetcertain performance standards. Thus, there exists a need for aplastic/mechanical system to perform in accordance with accepted firestandards. Also, introduction of resilient members to a plastic systemrequires that the CPVC pipe be subjected to new criteria of performancerelated to environmental stress crack resistance.

There exists a need for methods and devices for providing grooved CPVCpiping. Further, there exists a need in the art for an apparatusoperative to provide precise drilling of CPVC pipe for direct cut-in.

Fire sprinkler systems often use vertical risers to feed branches of thedistribution system. Often, metallic pipe is used for the risers thatfeed into the fire sprinkler system. The problem is that CPVC cannot beused in riser applications due to the need for adequate support of CPVCpiping without excessive compression of the material. Until now, themaximum diameter CPVC pipe used in fire sprinkler systems is about 2″.Thus, there exists a need for larger pipe diameters (up to 4″) with aclamping mechanism to allow the use of greater diameter pipes as thevertical risers.

SUMMARY OF THE INVENTION

In an exemplary embodiment, a system comprises a plurality of fluid pipelengths in fluid communication. The pipe lengths are formed of achlorinated polyvinyl chloride (“CPVC”) composition. The terms “CPVCcomposition” and “CPVC pipe” as used herein means that the CPVCcomposition and CPVC pipe has a continuous phase of CPVC polymer, thatis more than 50% by volume of the polymer components is CPVC, preferablymore than 70% and more preferably more than 80%. Other polymers can becombined with the CPVC polymer for improving impact resistance, flowenhancers, or other properties, but these other polymers are used insmaller amounts, normally from about 5-15 percent by weight.

In the exemplary system, a first type of mechanical fixture comprises acoupling device to sealingly engage a pair of pipe lengths in close endto end relationship without the use of solvent cement. Each pipe lengthhas an annular groove formed in the pipe wall a predetermined distancefrom its end. On each pipe segment, the pipe wall between the end andthe groove acts as a sealing surface. The coupling device includes aresilient annular seal comprised of a material chemically compatiblewith the CPVC composition which engages with the sealing surfaces.

A second exemplary type of mechanical fixture comprises a branchingdevice to sealingly engage a main pipe length and a branch pipe lengthin close perpendicular relationship at a branch location without the useof solvent cement. The branch pipe communicates with the main pipethrough an orifice in the main pipe. The branching device includes aresilient sealing member comprised of a material chemically compatiblewith the CPVC composition. A sealing surface of the resilient sealingmember is engaged with the main pipe length in a sealing areaimmediately about the orifice.

In an exemplary embodiment, when assembled, the coupling device and theat least one pair of pipe lengths comprise a first pipe fittingassembly, wherein the first pipe fitting assembly is operative to pass afirst predetermined testing protocol. When assembled, the branchingdevice, the main pipe length, and the branch pipe length comprise asecond pipe fitting assembly, wherein the second pipe fitting assemblyis operative to pass a second predetermined testing protocol.

In an exemplary embodiment, the system includes at least one verticalriser formed of a CPVC composition. The system further includes a thirdtype of mechanical fixture comprising a support device operative tosupportingly engage the at least one vertical riser. The support devicecomprises a pair of substantially identical band elements each operativeto embrace the wall of the riser throughout nearly 180°. Each bandelement includes an arcuate section, a flange, and an arm extension.When assembled, a flange surface and an arm extension surface of opposedband elements operate as a compression-limiting mechanism to preventover-compression of the CPVC riser.

In an exemplary embodiment, a method is provided for forming a system ofCPVC pipe lengths in fluid flow communication. The method includesreversibly sealingly engaging at least one pair of pipe lengths in closeend to end relationship without the use of solvent cement using a firsttype of mechanical fixture; and reversibly sealingly engaging at leastone main pipe length in close perpendicular relationship with at leastone branch pipe length at a branch location without the use of solventcement using a second type of mechanical fixture.

In an exemplary embodiment, there is provided a system comprising aplurality of CPVC pipe lengths in flow communication, wherein at least apair of CPVC pipe lengths are reversibly connected in close end to endrelationship via a first type of mechanical fixture, and at least oneCPVC main pipe length is reversibly connected in perpendicularrelationship with a CPVC branch pipe length via a second type ofmechanical fixture. The exemplary system includes a plurality of firesprinkler heads in flow communication with the plurality of pipelengths.

In an exemplary embodiment, there is provided a method comprisingforming pipe conduits of an initial CPVC composition for use in firesprinkler systems; forming first resilient sealing members comprising afirst material chemically compatible with the initial CPVC compositionfor use with mechanical fixtures for connecting the pipe conduits; andidentifying the first resilient sealing members as acceptable for usewith the pipe conduits.

The exemplary method further comprises forming modified pipe conduitscomprising a modified CPVC composition for use in fire sprinklersystems; forming second resilient sealing members comprising a secondmaterial chemically compatible with the modified CPVC composition foruse with mechanical fixtures for connecting the modified pipe conduits;and identifying the second resilient sealing members as acceptable foruse with the modified pipe conduits.

In an exemplary embodiment, there is provided a method comprising takinga region of a fire sprinkler system off-line, wherein the fire sprinklersystem comprises a network of existing pipe lengths comprising CPVC;modifying the fire sprinkler system by connecting at least oneadditional pipe length comprising CPVC in fluid flow communication withat least a portion of an existing pipe length using at least onemechanical fixture; and returning the region of the fire sprinklersystem to an on-line condition.

In an exemplary method, the fire sprinkler system is modified by squarecutting the existing pipe length to remove the section to be replacedand to provide at least a first pipe end; cutting an annular groove inthe pipe wall of the existing pipe length a predetermined distance formthe pipe end; providing a second pipe length having an annular groove inthe pipe wall a predetermined distance from an end thereof; andsealingly engaging the existing pipe length and the second pipe lengthin close end to end relationship with the at least one mechanicalfixture, wherein the at least one mechanical fixture is a couplingdevice.

In another exemplary method, the fire sprinkler system is modified bycutting an orifice in a main pipe length at a branch location; encasingthe main pipe length with the at least one mechanical fixture at thebranch location, wherein the mechanical fixture is a branching deviceoperative to sealingly engage the main pipe length about the orifice;and receiving a branch pipe length into an outlet opening in themechanical branching fixture, wherein the branch pipe length is disposedsubstantially perpendicularly to the main pipe length.

It is, therefore an object of an exemplary embodiment to provide a firesprinkler system utilizing CPVC piping wherein modifications and/orrepairs can be made to the system without the use of solvent cement andits associated cure time.

It is also an object of an exemplary embodiment to provide a method toensure compatibility between CPVC pipe lengths and the resilient sealingmembers employed in mechanical fixtures.

It is also an object of an exemplary embodiment to provide CPVC pipe andfitting assemblies capable of passing stringent testing protocols ofcertified testing authorities such as Underwriters Laboratories Inc.(UL).

It is also an object of an exemplary embodiment to provide a method forin-line joining of CPVC pipe lengths using grooved pipes and amechanical coupling device.

It is also an object of an exemplary embodiment to provide a method forforming a branch line in an existing fire sprinkler system utilizing amechanical branching device.

These, as well as other objects of exemplary embodiments will becomeapparent upon a consideration of the following detailed description anddrawings.

BRIEF DESCRIPTION OF THE DRAWINGS

The foregoing summary, as well as the following detailed description ofexemplary embodiments, will be better understood when read inconjunction with the appended drawings. For the purpose of illustratingthe invention, there is shown in the drawings certain exemplaryembodiments. It should be understood, however, that the invention is notlimited to the precise arrangements and instrumentalities shown. In thedrawings:

FIG. 1 is a schematic representation of an exemplary fire sprinklersystem comprising CPVC pipe lengths and mechanical fixtures;

FIG. 2 is a front view, partly in section, of a pair of pipe lengthsjoined end-to-end via a first type of mechanical fixture;

FIG. 3 is a perspective view of a seal member for use in the first typeof mechanical fixture;

FIG. 4 is a side view of a pipe length and mechanical fixture assembly;

FIG. 5 is a bottom view of a coupling segment of a coupling device;

FIG. 6 is a side view, partly in section, of a main pipe length and abranch pipe length joined via a second type of mechanical fixture;

FIG. 7 is a bottom view of a first arcuate section of a branchingdevice;

FIG. 8 is a sealing member for use in the second type of mechanicalfixture;

FIG. 9 is a top view, partly in section of a riser supported by a thirdtype of mechanical fixture;

FIG. 10 is a perspective view of a grooving tool;

FIG. 11 is a partial view of the grooving tool of FIG. 10 showing atension/depth guide;

FIG. 12 is a front view of a family of tension/depth guides; and

FIG. 13 is a partial perspective view of the grooving tool of FIG. 10and a grooved pipe length.

DETAILED DESCRIPTION OF THE INVENTION

With respect to FIG. 1, in an exemplary embodiment, a portion of firesprinkler system, generally indicated 10 includes a network of plasticpipe lengths 12 a, 12 b, 12 c, 12 d, 12 e which are formed ofchlorinated polyvinyl chloride (CPVC). The network of pipes are in flowcommunication with a plurality of fire sprinkler heads 14. The preferredtype of CPVC resin is sold under the BLAZEMASTER7 brand name. Anexemplary CPVC composition has physical and thermal characteristics asfollows:

BLAZEMASTER Property Brand CPVC ASTM Specific Gravity, “Sp. Gr.” 1.55D792 IZOD Impact Strength (ft.lbs./inch notched) 1.5 D256A Modulus ofElasticity, @73EF psi, “E” 4.23 × 10⁵ D638 Compressive Strength, psi,“o” 9,600 D695 Poisson's Ratio, “O” .35-.38 — Working Stress @ 73EF,psi, “S” 2,000 D1598 Hazen Williams Factor “C” 150 — Coefficient ofLinear Expansion,  3.4 × 10⁻⁵ D696 in/(in E F), “e” ThermalConductivity, BTU/hr/ft²/EF/in, “k” 0.95 D177 Flash IgnitionTemperature, EF 900 D1929 Limiting Oxygen Index, “LOI” % 60 D2863Electrical Conductivity Non Conductor — Extrusion Temperature 414-425 EFN/A (approx.) Heat Distortion Temperature, EF 217 —

In an exemplary embodiment, pipe lengths 12 a, 12 b may be joined inclose abutting end-to-end relationship to form in-line joints. In priorsystems, in-line joints between CPVC pipe lengths are formed using acoupler or socket extending between the two pipe lengths and adhered toeach pipe section via solvent cement. As illustrated, in this exemplaryembodiment, a first type of mechanical fixture or coupling device 16sealingly engages pipe lengths 12 a, 12 b in close abutting end to endrelationship. The use of a coupling device 16 eliminates the need forsolvent cement in this joint. Mechanical coupling fixtures are known foruse in joining metal to metal grooved end pipes. However, concerns aboutdiminished wall thickness, gasket compatibility, and over-compression ofpipes have deterred the use of conventional mechanical couplings withCPVC piping systems.

Mechanical fixtures are also known to be used to transition betweenmetal pipes and CPVC pipes using CPVC grooved adapters. The adapter isadhered to the CPVC piping via solvent cement. Heretofore, suchmechanical fixtures have not been used to join a pair of CPVC pipesegments. The known grooved adapters are molded to their final shape, aprocess very different from grooving an already formed pipe as will bediscussed in greater detail below.

In an exemplary embodiment, a main pipe length 12 c may be joined with abranch pipe length 12 d at a branch location 18 to form a tee-branch(T-branch). An additional branch pipe (shown in phantom in FIG. 1) maybe used to form a cross-branch (X-branch). A second type of mechanicalfixture or branching device 24 is utilized in a T-branch wherein acut-in orifice is made directly into the pipe wall of main pipe length12 c. A modified second mechanical fixture (not shown in this view) maybe utilized to form an X-branch wherein a second orifice is cut in thepipe wall of main pipe length 12 c diametrically opposed to the firstorifice, as will be explained in further detail below.

Also, in the exemplary embodiment, CPVC piping is utilized for thevertical riser 12 e. Use of CPVC piping for vertical risers presentschallenges not encountered by metal risers. In the exemplary embodiment,a third type of mechanical fixture or support device 30 is utilized tosupport the riser.

As shown in FIG. 2, the pipe lengths 12 a, 12 b each include an annularexternal groove 32, 34 axially spaced from respective ends 36, 38 of thepipe lengths 12 a, 12 b. Pipe length 12 a includes an annular sealingsurface portion 40 disposed between groove 32 and end 36. Likewise, pipelength 12 b includes an annular sealing surface portion 42 betweengroove 34 and pipe end 38.

As best shown in FIGS. 3 and 4, coupling device 16 includes an annularresilient sealing member 46 that in the operative position sealinglyengages the annular sealing surface portions 40, 42. The material fromwhich seal 46 is formed must be compatible with the CPVC composition toavoid degradation or the formation of stress cracks in the pipe. In anexemplary embodiment, sealing member 46 may include a bifurcatedinternal sealing surface 47.

With reference to FIGS. 4 and 5, in this exemplary embodiment, couplingdevice 16 includes a pair of coupling segments 48, 50 that may be ofsubstantially identical construction. Therefore, for simplicity, onlythe construction of segment 48 will be described in detail. Couplingsegment 48 comprises an arcuate body 54 having a first end 56, a secondend 58, and an interior concave surface 60 extending between the firstend and the second end. A longitudinal channel 62 extends along theconcave surface 60 from first end 56 to second end 58. The longitudinalchannel 62 is designed to receive the sealing member 46. In thisexemplary embodiment, a flange 64 extends from each end 56, 58 and eachflange has a fastener hole 66 therethrough.

When the coupling device 16 is in an assembled condition, the first andsecond ends of one of the coupling segments are presented to therespective first and second ends of the other coupling segment. Seal 46is engaged in an interior circumferential region 70 which includes thelongitudinal channels 62 and which is bounded by the interior concavesurfaces 60 (shown in FIG. 2). In this exemplary embodiment, a pair ofmechanical fasteners 72 are utilized to connect the pair of couplingsegments. Each flange 64 includes a generally planar surface 65 adaptedto abut a corresponding surface on the other coupling segment. Theengagement of these surfaces provide a means to limit compression forcesexerted on the pipe lengths 12 a, 12 b. In the exemplary embodiment, thearcuate body 54 is generally manufactured from ductile iron, although inother embodiments other materials may be used.

When assembled, the coupling device and the pair of pipe lengthscomprise a first pipe fitting assembly that is operative to pass atesting protocol as will be described in greater detail below.

With reference again to FIG. 1, in the exemplary embodiment, the secondtype of mechanical fixture or branching device 24 is employed for cut-intee (T) connections. In an alternate embodiment, a modified branchingdevice is utilized for cut-in cross (X) connections.

As illustrated in FIG. 6, branching device 24 is adapted for use with amain pipe length 12 c having a cut-in orifice 76 to enable fluid flowcommunication between main pipe length 12 c and branch pipe 12 d.Orifice 76 is round, i.e., the projection of a circle on the pipe wall.Main pipe length 12 c and branch pipe length 12 d are disposed so thattheir longitudinal axes are in perpendicular relationship.

Branching device 24 includes a resilient sealing member 78 comprised ofa material chemically compatible with the CPVC composition of which thepipe lengths 12 are formed. The resilient sealing member 78 may beformed of the same material as annular seal 46, or they may be formed ofdifferent material, so long as each is compatible with the CPVC.

With reference to FIGS. 6 and 7, branching device 24 includes first andsecond arcuate sections 80, 82, respectively. First arcuate section 80includes a concave saddle surface 84 generally corresponding to theouter circumference of main pipe length 12 c. A branch pipe opening 86is surrounded by a spigot wall 88. Exemplary spigot wall 88 includes acontoured lip 90 adapted to generally correspond to the curvature oforifice 76. A sealing recess 94, extending in the saddle surface 84,encircles the spigot wall 88. The sealing recess 94 is adapted togenerally conform to the curvature of the outer diameter of main pipelength 12 c. The first arcuate section 80 embraces the outer wall of themain pipe length 12 c throughout substantially 180E and reinforces thepipe length at the location of orifice 76.

With reference to FIG. 6, second arcuate section 82 includes an interiorconcave surface 98 that is generally adapted to conform to thecircumference of main pipe length 12 c. When the branching device 24 isassembled, sealing member 78 is seated in the sealing recess 94. In thisembodiment, a pair of mechanical fasteners 100 is utilized to join thefirst and second arcuate sections 80, 82. Each arcuate section 80, 82includes a substantially planar region 104 adapted to abut acorresponding planar region on the other opposed arcuate section. Theseregions serve as a compression-limiting device when main pipe length 12c is encased in branching device 24.

With reference to FIG. 8, resilient sealing member 78 in the undeformedcondition comprises a saddle-shaped body 106 having a central openingtherethrough. A first surface 108 is contoured to generally conform tothe shape of the closed end of sealing recess 94. An opposed sealingsurface 110 is contoured to conform to the contour of outer pipe wall ofmain pipe length 12 c. In this exemplary embodiment, resilient sealingmember 78 includes two opposed key projections 112. Key projections 112are adapted to cooperate with a key recesses 114 of sealing recess 94 tofacilitate properly orienting the resilient sealing member within thesealing recess 94. In the assembled condition the resilient sealingmember engages the outer pipe wall and is compressed to form a fluidtight annular seal in surrounding relation of orifice 76. Whenassembled, the branching device, the main pipe length, and the branchpipe length comprise a second pipe fitting assembly that is operative topass a testing protocol as described below.

In an alternate exemplary embodiment, illustrated in phantom in FIG. 1,a modified branching device may be utilized to form a cross-branch. Twoarcuate sections 80 and two resilient sealing members 78 are utilized toencase a main pipe length having diametrically opposed orifices formedtherein.

With reference again to FIG. 1, the exemplary system 10 includes atleast one vertical riser 12 e formed of CPVC material. Particularly, theexemplary system provides a CPVC vertical riser 12 e wherein the pipediameter is greater than 2≅, and preferably 4″ or more. With referenceto FIG. 9, support device 30 includes a pair of substantially identicalband elements 120. Each band element 120 includes an arcuate section 122adapted to embrace the wall of the riser 12 e throughout nearly 180E.Each band element 120 further includes a flange portion 124 having agenerally planar flange surface 126 extending in perpendicularrelationship from a first end of arcuate section 122. Flange surface 126has an opening therethrough for reception of a mechanical fastener 128.Arm extension 132 comprises a generally planar surface 134 extending inperpendicular relationship from the second end of arcuate section 122.Arm extension also includes an opening therethrough for reception of amechanical fastener 128. Arm extension 132 is adapted for connectionwith structural members to stabilize vertical riser 12 e. The exemplarysupport device 30 is formed of metal in an exemplary embodiment, but inother embodiments other materials may be used.

Use of larger diameter CPVC pipe lengths, such as riser 12 e, presentsunique challenges for the pipe and support assembly. For example, thepipe length must be supported without over-compression of the pipe wall.Thus, compression tolerances must be considered in the construction ofthe mechanical fixture. Also, material expansion and contraction must betaken into account. Further, the exemplary system 10 is contemplated foruse in a continuously pressurized wet fire sprinkler system.

When the support device 30 is assembled and in operative conditionsupporting the riser, the flange surface 126 of one element is adaptedto abut the flange surface 126 of the other opposed element. Likewise,the arm extension planar surface 134 of one element is adapted to abutthe arm extension planar surface 134 of the other opposed element. Thisarrangement acts as a compression-limiting mechanism to preventcompression of the CPVC riser beyond predetermined compression limits.

An exemplary method includes forming a system of pipe lengths 12 influid flow communication, wherein the pipe lengths are formed of a CPVCcomposition. In forming the system, at least one pair of pipe lengths 12a, 12 b is sealingly engaged in close end-to-end relationship withoutthe use of solvent cement. Instead, the at least one pair of pipelengths is reversibly and releasably sealingly engaged with a first typeof mechanical fixture or coupling device 16.

In an exemplary method, at least one main pipe length 12 c and at leastone branch pipe 12 d are sealingly engaged in close perpendicularrelationship at a branch location without the use of solvent cement. Themain pipe length and the branch pipe are reversibly and releasablyengaged with a second type of mechanical fixture or branching device 24.

An exemplary method includes subjecting a first pipe fitting assemblycomprising the pair of pipe lengths and the coupling device to a testingprotocol. A second pipe fitting assembly comprising the main pipelength, the branch pipe, and the branching device is also subjected to atesting protocol.

In an exemplary method, the step of sealingly engaging the pair of pipelengths includes forming a continuous annular groove 32, 34 in a pipewall of each of the pipe lengths 12 a, 12 b a predetermined distancefrom an end thereof. A resilient annular seal 46, formed of a materialchemically compatible with the CPVC pipe, is positioned onto sealingsurfaces 40, 42 located between each respective groove and pipe end.Thereafter, a pair of coupling segments is positioned about the annularseal such that the seal is seated in an interior longitudinal channel 62of each coupling segment which forms the interior circumferential region70.

With reference to FIGS. 10-13 in an exemplary embodiment a pipe groove32 is formed using a grooving tool 120. The end of the pipe of theembodiment is preferably cut square so that a sealing surface at the endof the pipe may be formed according to controlling specifications.

A cutting blade 124 is selected based on the pipe diameter. For example,in the exemplary method, for pipes in sizes 2 to 3 inches in diameter ablade is used with a width of about 0.312 inches. For a pipe with a4-inch diameter a blade with a width of about 0.375 inches may be used.The blades cut a groove of substantially corresponding width into thethickness of the pipe wall. Of course this approach is exemplary.

The blade 124 is supported by a top support 126 to prevent the bladefrom moving front to back. Bushings 128 are installed to prevent theblade from moving side to side. In the exemplary method, bushings areused on both sides of the blade for the 0.312 inch blade. For the 0.375inch blade, a bushing is used on only one side (the “A” side) of theblade. In that way, the blade can be readily changed without making anadjustment to the cutting guide for the “A” dimension as detailed below.

In the exemplary method, a tension/depth guide 132 is utilized to limitthe tension and depth of the groove 32 formed in the pipe wall. Theexemplary tension/depth guide may be adjusted as needed. A locking nut134 is installed to keep the setting constant. In the exemplary method,interchangeable tension/depth guides 132 a, 132 b, 132 c, 132 d areprovided and a selection is made according to pipe size.

In the exemplary method, a cutting guide 138, aligned with the edge 140of the pipe, is utilized to maintain the proper size of the longitudinalsealing surface 40 adjacent the end of the pipe. The distance from thegroove 32 to the pipe edge 140 is termed the “A” dimension which is thewidth of the sealing surface 40. In the exemplary embodiment the cuttingguide 138 can he adjusted as needed. A locking nut 142 is installed tomaintain the setting of the cutting guide. The groove walls which extendgenerally perpendicular to the annular outer surface of the pipe can bestraight cut, or radiused in some embodiments.

With the pipe length 12 a properly positioned, the outer pipe wall isengaged with the blade 124 by rotation of tensioning handle 146. Thegrooving tool 120 is then rotated relative to the pipe with the cuttingblade 124 removing pipe material. The tensioning handle is rotated somaterial is removed on each subsequent pass. The process continues untilno further pipe material is removed due to action of the tension depthguide. As the grooving tool is rotated, the cutting guide 138 should bemonitored to ensure that the pipe edge 140 is riding along the cuttingguide to maintain the proper width for sealing surface 40.

After the initial groove is formed, the groove diameter is measured toverify that the groove diameter is within specifications. If necessary,the tension/depth guide 132 is adjusted, and the grooving processrepeated. The “A” dimension is measured to verify that the sealingsurface 40 is within specifications. The cutting guide 138 is adjustedif required and the grooving process repeated.

In an exemplary method, the step of sealingly engaging the main pipelength 12 c with the branch pipe 12 d includes forming an orifice 76 inthe main pipe length at a branch location. The pipe wall of the mainpipe length is embraced with a branching device 24 comprising first andsecond arcuate sections 80, 82 such that a sealing member 78 carried ina sealing recess 94 in a first arcuate section compressively engages themain pipe length about the orifice.

In the exemplary method, a branch cutting tool (not shown) is utilizedto cut the orifice in the main pipe length at the branch location. Theexemplary branch cutting tool is able to retain the cut-out coupon sothat it does not enter the main pipe length.

UL Testing for Mechanical Connectors:

One objective of the exemplary embodiments disclosed herein is that thepipe and mechanical fixture assemblies will be able to meet or exceed ULtesting requirements for use in fire sprinkler systems. A few of thetests to which the pipe fitting assemblies would be subjected arebriefly described below.

Fire Exposure Test (UL 1821, Sec 13)

Representative pipe and fitting assemblies for ceiling pendent, upright,and sidewall pendent shall be tested.

Exposed pipe and fitting assemblies:

-   -   a) shall not burn, separate, or leak; and    -   b) shall maintain the sprinkler in the intended operating        position.

Following the fire exposure, the pipe and fitting assemblies shallwithstand an internal hydrostatic pressure equal to the maximum ratedpressure for 5 minutes without rupture or leaks.

Bending Moment Tests (UL 213, Sec. 12):

Testing will be conducted with all sizes of tees and crosses whichinclude a threaded outlet connection except ½ and ¾ in. outlets.

The fitting and pipe joint assembly shall not leak or rupture whensubjected to the specified bending moment. During the tests the assemblyis to be pressurized to rated pressure.

The required bending moment is calculated based on twice the weight ofwater filled pipe over twice the maximum distance between pipe supportsspecified in the Standard for Installation of Sprinkler Systems,ANSI/NFPA 13.

CPVC Bending Moments Pipe Size H2O filled (lbs/ft) Hanger (feet) Moment(ft-lbs) 1″ 0.675 6 24.3 1¼″ 1.079 6.5 45.6 1½″ 1.417 7 69.6 2≅ 2.224 8142.3 2½″ 3.255 9 263.7 3 4.829 10 482.9

With the assembly support at point located at least 12 inches (305 mm)on either side of the center of the coupling, a gradually increasingforce is to be applied to the center of the coupling until the requiredbending moment is achieved.

Vibration Test (UL 1821, Sec. 19)

Testing will be conducted with 2×1 threaded outlet and 2×1¼ inch groovedoutlet tees and 2½×1 threaded outlet, 2½×1¼ grooved outlet, 3×1½ inchthreaded and grooved crosses. The 2½ inch cross will have a 1 inchthreaded outlet on one side and a 1¼ inch grooved outlet on the otherside. The 3 inch cross will have a 1½ inch threaded outlet on one sideand a 1½ inch grooved outlet on the other side.

Pipe and fitting assemblies shall withstand the effects of vibration for30 hours without deterioration of performance characteristics. Followingthe vibration test, each test assembly shall comply with the specifiedrequirements in the Hydrostatic Pressure Test.

Assembly Test (UL 1821, Sec. 22)

Testing will be conducted with all combinations of pipe size and holesize for both tees and crosses.

Samples shall withstand for 2 hours, without rupture, separation, orleakage, an internal hydrostatic pressure equivalent to the ratedpressure or higher, as specified in the installation and design manual,and other internal hydrostatic pressures as they relate to cure timesspecified in the installation and design manual.

Hydrostatic Pressure Test (UL 1821, Sec. 23)

Testing will be conducted with all combinations of pipe size and holesize for both tees and crosses.

Representative pipe and fitting assemblies shall withstand for 1 minute,without rupture, separation, or leakage, an internal hydrostaticpressure of five times the rated pressure.

Pressure Cycling Test (UL 1821, Sec. 24)

Testing will be conducted with all combinations of pipe size and holesize for both tees and crosses.

Representative pipe and fitting assemblies shall withstand withoutleakage, separation, or rupture 3000 pressure cycles from zero to twicethe rated pressure of the pipe and fittings. After the cycling, the pipeand fitting assemblies shall comply with the Hydrostatic Pressure Test.

Temperature Cycling Test (UL 1821, Sec. 25)

Testing will be conducted with all combinations of pipe size and holesize for both tees and crosses.

Representative pipe and fitting assemblies shall comply with theHydrostatic Pressure Test after being subjected to temperature cyclingfrom 35° F. (1.7° C.) to the maximum rated temperature. The pipe andfitting assemblies are to be filled with water, vented of air,hydrostatically pressurized to 50 psig (345 kPa), and subjected totemperature cycles of 35EF (1.7EC) to the maximum rated temperature to35EF. Each assembly is to be held at each temperature specified for aperiod of 24 hours. A total of 5 complete cycles are to be completed.

Long Term Hydrostatic Pressure Test (UL 1821, Sec. 27)

Testing will be conducted with all combinations of pipe size and holesize for both tees and crosses.

The pipe and fitting assemblies shall withstand without rupture,leakage, or joint separation the hoop stress specified below, applied tothe assembly for 1000 hours, at the maximum rated temperature:

Type Standard dimension ratio Reuired hoop stress, psi (Mpa) CPVC 13.52310 (15.93) During and after exposure, the pipe and fitting assembliesare to be examined for evidence of rupture, leakage, or jointseparation.

Thus, the exemplary apparatus and processes for forming a network ofCPVC pipe lengths achieve one or more of the above stated objectives.

In the foregoing description, certain terms have been used for brevity,clarity and understanding, however, no unnecessary limitations are to beimplied therefrom, because such terms are used for descriptive purposesand are intended to be broadly construed. Moreover, the descriptions andillustrations herein are by way of examples and the invention is notlimited to the exact details shown and described.

In the following claims, any feature described as a means for performinga function shall be construed as encompassing any means known to thoseskilled in the art to be capable of performing the recited function, andshall not be limited to the features and structures shown herein or mereequivalents thereof. The description of the exemplary embodimentincluded in the Abstract included herewith shall not be deemed to limitthe invention to features described therein.

Having described the features, discoveries and principles of theinvention, the manner in which it is constructed and operated, and theadvantages and useful results attained; the new and useful structures,devices, elements, arrangements, parts, combinations, systems,equipment, operations, methods and relationships are set forth in theappended claims.

1-27. (canceled)
 28. An assembly comprising: first and second pipelengths comprising a CPVC composition; and a mechanical fixtureoperative to sealingly engage the first and second pipe lengths, whereinwhen assembled, the assembly is operative to pass a first predeterminedtesting protocol.
 29. The assembly of claim 28 wherein the firstpredetermined testing protocol comprises at least one member of thegroup consisting of a Fire Exposure Test, UL 1821, Sec 13; a BendingMoment Test, UL 213, Sec. 12; a Vibration Test, UL 1821, Sec. 19; anAssembly Test, UL 1821, Sec. 22; a Hydrostatic Pressure Test, UL 1821,Sec. 23; a Pressure Cycling Test, UL 1821, Sec. 24; a TemperatureCycling Test, UL 1821, Sec. 25; a Long Term Hydrostatic Pressure Test,UL 1821, Sec. 27; and combinations thereof.
 30. The assembly of claim 28wherein: each of the pipe lengths includes a continuous annular grooveformed in the pipe wall at a predetermined distance from an end thereof,wherein the portion of the pipe wall on each pipe length between thepipe end and the groove comprises a sealing surface, and wherein thefirst and second pipe lengths are in close end to end relationship witheach other; and wherein the mechanical fixture comprises a couplingdevice including a resilient seal, wherein the resilient seal isoperative to annularly engage the sealing surfaces and to span the endsof the pipe lengths, wherein the seal comprises a material chemicallycompatible with the CPVC composition.
 31. The assembly of claim 28wherein: the first pipe length is a main pipe length and the second pipelength is a branch pipe length, wherein the main pipe length and thebranch pipe length are in close perpendicular relationship with eachother, wherein the main pipe length includes at least one orificetherein at a branch location; and the mechanical fixture comprises abranching device including a first arcuate section, wherein the firstarcuate section includes a concave saddle surface generallycorresponding to the outer circumference of the main pipe length, abranch pipe opening dimensioned to extend in the orifice, a spigot wallsurrounding the branch pipe opening wherein the spigot wall terminatesinwardly at a contoured lip generally corresponding to the saddlesurface contour, and a sealing recess encircling the spigot wall whereinthe sealing recess is open at the saddle wall and terminates in thedirection of the branch pipe; a second arcuate section having a surfaceoperative to embrace the main pipe length; a resilient sealing memberpositioned in the sealing recess, wherein the sealing member isannularly engaged with the pipe length about the orifice, and whereinthe resilient sealing member is chemically compatible with the CPVCcomposition; and at least one mechanical fastener operative to engagethe first arcuate section with the second arcuate section.